xref: /dragonfly/lib/libc/net/inet6_rth_space.3 (revision 19fe1c42)
1.\"	$KAME: inet6_rth_space.3,v 1.7 2005/01/05 03:00:44 itojun Exp $
2.\"
3.\" Copyright (C) 2004 WIDE Project.
4.\" All rights reserved.
5.\"
6.\" Redistribution and use in source and binary forms, with or without
7.\" modification, are permitted provided that the following conditions
8.\" are met:
9.\" 1. Redistributions of source code must retain the above copyright
10.\"    notice, this list of conditions and the following disclaimer.
11.\" 2. Redistributions in binary form must reproduce the above copyright
12.\"    notice, this list of conditions and the following disclaimer in the
13.\"    documentation and/or other materials provided with the distribution.
14.\" 3. Neither the name of the project nor the names of its contributors
15.\"    may be used to endorse or promote products derived from this software
16.\"    without specific prior written permission.
17.\"
18.\" THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28.\" SUCH DAMAGE.
29.\"
30.\" $FreeBSD: src/lib/libc/net/inet6_rth_space.3,v 1.10 2005/07/31 03:30:44 keramida Exp $
31.\" $DragonFly: src/lib/libc/net/inet6_rth_space.3,v 1.2 2008/09/05 20:43:08 swildner Exp $
32.\"
33.Dd September 4, 2008
34.Dt INET6_RTH_SPACE 3
35.Os
36.\"
37.Sh NAME
38.Nm inet6_rth_space ,
39.Nm inet6_rth_init ,
40.Nm inet6_rth_add ,
41.Nm inet6_rth_reverse ,
42.Nm inet6_rth_segments ,
43.Nm inet6_rth_getaddr
44.Nd IPv6 Routing Header Options manipulation
45.\"
46.Sh LIBRARY
47.Lb libc
48.Sh SYNOPSIS
49.In netinet/in.h
50.Ft socklen_t
51.Fn inet6_rth_space "int type" "int segments"
52.Ft "void *"
53.Fn inet6_rth_init "void *bp" "socklen_t bp_len" "int type" "int segments"
54.Ft int
55.Fn inet6_rth_add "void *bp" "const struct in6_addr *addr"
56.Ft int
57.Fn inet6_rth_reverse "const void *in" "void *out"
58.Ft int
59.Fn inet6_rth_segments "const void *bp"
60.Ft "struct in6_addr *"
61.Fn inet6_rth_getaddr "const void *bp" "int idx"
62.\"
63.Sh DESCRIPTION
64The IPv6 Advanced API, RFC 3542, defines the functions that an
65application calls to build and examine IPv6 Routing headers.
66Routing headers are used to perform source routing in IPv6 networks.
67The RFC uses the word
68.Dq segments
69to describe addresses and that is the term used here as well.
70All of the functions are defined in the
71.In netinet/in.h
72header file.
73The functions described in this manual page all operate
74on routing header structures which are defined in
75.In netinet/ip6.h
76but which should not need to be modified outside the use of this API.
77The size and shape of the route header structures may change, so using
78the APIs is a more portable, long term, solution.
79.Pp
80The functions in the API are split into two groups, those that build a
81routing header and those that parse a received routing header.
82We will describe the builder functions followed by the parser functions.
83.Ss inet6_rth_space
84The
85.Fn inet6_rth_space
86function returns the number of bytes required to hold a Routing Header
87of the type, specified in the
88.Fa type
89argument and containing the number of addresses specified in the
90.Fa segments
91argument.
92When the type is
93.Dv IPV6_RTHDR_TYPE_0
94the number of segments must be from 0 through 127.
95Routing headers of type
96.Dv IPV6_RTHDR_TYPE_2
97contain only one segment, and are only used with Mobile IPv6.
98The return value from this function is the number of bytes required to
99store the routing header.
100If the value 0 is returned then either the
101route header type was not recognized or another error occurred.
102.Ss inet6_rth_init
103The
104.Fn inet6_rth_init
105function initializes the pre-allocated buffer pointed to by
106.Fa bp
107to contain a routing header of the specified type The
108.Fa bp_len
109argument is used to verify that the buffer is large enough.
110The caller must allocate the buffer pointed to by bp.
111The necessary buffer size should be determined by calling
112.Fn inet6_rth_space
113described in the previous sections.
114.Pp
115The
116.Fn inet6_rth_init
117function returns a pointer to
118.Fa bp
119on success and
120.Dv NULL
121when there is an error.
122.Ss inet6_rth_add
123The
124.Fn inet6_rth_add
125function adds the IPv6 address pointed to by
126.Fa addr
127to the end of the routing header being constructed.
128.Pp
129A successful addition results in the function returning 0, otherwise
130\-1 is returned.
131.Ss inet6_rth_reverse
132The
133.Fn inet6_rth_reverse
134function takes a routing header, pointed to by the
135argument
136.Fa in ,
137and writes a new routing header into the argument pointed to by
138.Fa out .
139The routing header at that sends datagrams along the reverse of that
140route.
141Both arguments are allowed to point to the same buffer meaning
142that the reversal can occur in place.
143.Pp
144The return value of the function is 0 on success, or \-1 when
145there is an error.
146.\"
147.Pp
148The next set of functions operate on a routing header that the
149application wants to parse.
150In the usual case such a routing header
151is received from the network, although these functions can also be
152used with routing headers that the application itself created.
153.Ss inet6_rth_segments
154The
155.Fn inet6_rth_segments
156function returns the number of segments contained in the
157routing header pointed to by
158.Fa bp .
159The return value is the number of segments contained in the routing
160header, or \-1 if an error occurred.
161It is not an error for 0 to be
162returned as a routing header may contain 0 segments.
163.\"
164.Ss inet6_rth_getaddr
165The
166.Fn inet6_rth_getaddr
167function is used to retrieve a single address from a routing header.
168The
169.Fa index
170is the location in the routing header from which the application wants
171to retrieve an address.
172The
173.Fa index
174parameter must have a value between 0 and one less than the number of
175segments present in the routing header.
176The
177.Fn inet6_rth_segments
178function, described in the last section, should be used to determine
179the total number of segments in the routing header.
180The
181.Fn inet6_rth_getaddr
182function returns a pointer to an IPv6 address on success or
183.Dv NULL
184when an error has occurred.
185.\"
186.Sh EXAMPLES
187RFC 3542 gives extensive examples in Section 21, Appendix B.
188.Pp
189KAME also provides examples in the advapitest directory of its kit.
190.\"
191.Sh DIAGNOSTICS
192The
193.Fn inet6_rth_space
194and
195.Fn inet6_rth_getaddr
196functions return 0 on errors.
197.Pp
198The
199.Fn inet6_rthdr_init
200function returns
201.Dv NULL
202on error.
203The
204.Fn inet6_rth_add
205and
206.Fn inet6_rth_reverse
207functions return 0 on success, or \-1 upon an error.
208.\"
209.Sh SEE ALSO
210.Rs
211.%A W. Stevens
212.%A M. Thomas
213.%A E. Nordmark
214.%A T. Jinmei
215.%T "Advanced Sockets API for IPv6"
216.%N RFC 3542
217.%D May 2003
218.Re
219.Rs
220.%A S. Deering
221.%A R. Hinden
222.%T "Internet Protocol, Version 6 (IPv6) Specification"
223.%N RFC 2460
224.%D December 1998
225.Re
226.Sh HISTORY
227The implementation first appeared in KAME advanced networking kit.
228